Aero Design Senior Project Community Ideas
 

I am currently working on a senior project that revolves around designing, 3D printing and scale model wind tunnel testing various wings, spoilers and other rear attachments (not diffusers at least not yet anyway). Each wing/spoiler is attached to the trunk. I am reaching out to the community for designs for wings/spoilers. I have a few (~14) but I would like more. In addition, if there is anything you would like me to test for you, please let me know. The car is a 1/24th scale EM1 Civic Coupe. The wings will be tested for drag and downforce/lift. I may or may not be able to translate these into real world values but at the very least they can be compared to one another (and stock).

Thanks for taking to the time to read this.

How bout testing a bonneville flat spoiler - on rear of trunk?

OK, I'll say it. Sounds like a cool project. However, the spoilers on the trunks of cars are not a significant aerodynamic feature when it comes to ecomodding. Even if optimally designed, the spoilers offer only a very small MPG gain. However, they may have a significant impact in the negative light on MPG if done improperly.

Still an interesting project with possible insights for high performance applications with high speed and handling aspects.

It's the overall shape of the car that results in its ultimate Cd, since the trunk spoiler area is such a small part of the overall design, and is in the very turbulent wake area, it's ability to have a large impact isn't that big.

Prepare yourself for only very small variations from one design to the next.

Sixth generation (1995–2000) – EK2, EK3, EK4, EK5, EK9, EJ6, EJ7, EJ8, EJ9, EM1
https://en.wikipedia.org/wiki/Honda_Civic
Using the forum's "Aero-Template" as a starting point.
Aerodynamics by George Kachadoorian | Photobucket
http://i184.photobucket.com/albums/x...psppsy2zlb.jpg

My guess is that anything beneath the red line and in the green area will have little affect.

On second thought, something right up to that line like the early Ducktail on a Porsche 911 (1973-1974 RS) should reduce lift by getting flow closer to the template.

What I meant to say is the wing on the red car is not in the flow and does little.

Wings; should be placed above the green area for maximum affect.

Spoilers; should be placed at or below the green area for maximum benefit.

The biggest challenge in conversation is in discussing spoilers which look like wings but are really spoilers as they allow no air flow underneath the alleged wing.

This has been a big problem in the forum before.

There may be little discovery of many new forms for these cars as they are the most riced out in history with aftermarket accessories. Could be a public service testing what's currently out there. And then from that data base create your new form/shape.

EDIT: If anyone can find a better side view please post it, I had a devil of a time just finding this one.

Rumdog - I have designed many wings (or spoilers?) of that style

ChazInMT - You're more correct than I'm sure you could ever imagine haha. I have two different setups, one to test downforce and one to test drag. The one for downforce works beautifully, but the drag one has been having issues of not reading enough on the force gauge to see any differences. With any luck this issue will be fixed by next week.

kach22i - I actually did test a ducktail for one of my designs. Look up a Rocket Bunny 240z to see a similar style wing. Strangely enough at both high (40 mph) and low speed, the spoiler zeroed out the lift of the car. For a good side view, google "civic coupe dimensions".

That is a pretty good search phrase, however I don't trust anything I see, they ain't worth a darn.

I have a pretty good eye and so far nothing I see is more accurate than the perspective ridden view already posted.

Who draws these things, drunken Russian teenagers?

EDIT:
Might be a 1999-2000 2-door Honda Civic in this thread, no guarantees.

http://ecomodder.com/forum/showthrea...ead-26678.html

I could try taking a picture of my model. I have a legit camera but I don't know how good I can get it. Precision is not really the main focus here. All the wings are attached by hand for instance. I'm kind of more looking for general ideas for shapes and such rather than discreet dimensions.

Sounds like you have a good foundation and understanding already.

What I think perhaps is a neglected aspect of rear spoiler and wing design is the termination edges. That is to say the corners and also plan view alterations from being so monolithic and straight planed.

As a guide look at the tip of aircraft wings or winglets which attend to the pressure differences which create vortexes as having more variations and innovations than NACA wing sections. Some of these wing tips are inspired by nature (bird wings) for instance.

I think it would be great if rear spoilers were given similar attention.

For instance, take your Rocket Bunny 240z; what if the corners had little wavy edges to break up resonance nodes and to mediate various angles of attack found in turning/curves?

Cars may be driven mostly in straight lines, but recent CFD studies are including various geometries of the vehicle in motion in a more 3D sense than in previous decades.

So there you go, my concept deals with plan view sweeps and curves to cup or deflect the air flow and air pressure. Coupled with top edge and corner treatment of spoiler shapes, undulating/wavy/curved/serrated and so forth.

Background: my hovercraft experiments dealt with sound mostly, sound is wasted energy or energy built up at specific frequencies. The splitter on my hovercraft spread some of this energy around to lower peak levels. If such an ideology were applied to a rear spoiler there could be a greater range of use out of it (useful speeds and or angles of attack).

Making Curves - is this one way? - Boat Design Forums
http://i184.photobucket.com/albums/x...22i/HOV102.jpg

My Photobucket:
George Kachadoorian's Library | Photobucket
http://i184.photobucket.com/albums/x...22i/HOV103.jpg

Related old thread;
http://ecomodder.com/forum/showthrea...ign-22101.html
http://i184.photobucket.com/albums/x...22i/HOV104.jpg

One really good response to that old thread:

As far as winglets are concerned, I believe you are referring to what are called endplates in terms of cars. There is a good example on Mulsanne's Corner and I have uploaded an image of one of the wings I designed (it has something similar to a NACA 4412 airfoil flipped upside down) and there end plates on it although they are built into the mounts. imgur. com/a/PhFcd (I don't have enough posts to post links yet).

I am having a hard time understanding what you are getting at with the wavy corners. Is there any way you could sketch something out so I could get a better idea. I'm not really knowledgeable enough to understand the acoustic side of aerodynamics. I've never really looked into it.

A picture is worth a thousand words, these two designs do not curve in plan, would have to draw by hand to illustrate that intent. Maybe will do later.

Again, this isn't for looks (selling/marketing), it's for testing and exploring an idea.

Started with this image off the Internet, used a really crude photo editing program. I can draw, but wanted to keep this simple to start with.

Aerodynamics by George Kachadoorian | Photobucket
http://i184.photobucket.com/albums/x...pslbfynrhv.jpg


http://i184.photobucket.com/albums/x...psuc5pwdyg.jpg

http://i184.photobucket.com/albums/x...pszdx772pu.jpg

Taking it a bit further.

http://i184.photobucket.com/albums/x...pslc9ebzzn.jpg

http://i184.photobucket.com/albums/x...psyj8hc6s6.jpg

Now I made you all hungry for the wrong foods, right?

https://www.walmart.com/ip/Great-Val...16-oz/46460985
http://i5.walmartimages.com/dfw/dce0...98639b1.v1.jpg

I would expect these designs to break up the edge pressure differentials similar to they way they for frequency nodes for sound. The advantage is less lost energy to peaks and transitions. The mass of air would still behave the same I suspect, the interactions at the top edges would be flattened out, an irony considering all the curves and undulations.

You wanted something to test, be careful what you ask for.:)

Will you be testing both wings and spoilers?

Will you be able to test combinations of both?

Yes, F1 cars have one type of plate at the wing ends because of regulations, I'm guessing you are exploring ideas outside of these restrictions - yes?

Just think if these fins below had been curved inward - the possibilities for down-force and stability with minimum surface area/drag.

Looking for 1963 Le Mans Panhard Cd blueprints
http://ecomodder.com/forum/showthrea...nts-33026.html
http://www.autodrome.fr/CD%20Avignon%202010%20008.JPG

http://www.talkativeman.com/graceful...rbus_a350_xwb/
http://www.talkativeman.com/img/Shar...s_A350_XWB.jpg

http://www.autodrome.fr/cd_panhard_l...64_english.htm
http://i184.photobucket.com/albums/x...psjmuvbhm3.jpg

I threw together something similar. Unfortunately in a huge extrusion, inventor wasn't happy so hopefully you can get the gist of it. imgur.com/ a/9pCMY

I can basically test anything I can attach to the car and will fit inside the wind tunnel. End plates on F1 cars aren't really a regulation thing, it's more to prevent flow on the very edge of the wing (tip) from bleeding over the sides and creating turbulence. The reason why planes have them like that is that you want to minimize the bleed while also minimizing surface area. Minimizing the bleed means minimizing loss of lift and reducing drag somewhat. Winglets or end plates don't inherently create downforce/lift, they only aid the accompanying airfoil in producing downforce/lift. I'm not an expert but I would imagine curving those fins in wouldn't do much of anything except maybe increase stability. Unless they were airfoils like on the Ferrari FXX http://auto.ferrari.com/en_EN/wp-con...-FXXK33169.jpg

Could you please try reposting that link?

I understand your explanation and the differences and agree with it more or less. However everything is regulated in race car design, which is why you get all those weird and exotic shapes out of them - bending the rules as it were.

How much of your grade is based on understanding and testing basic principals, and how much is for creativity or innovation?

There is the danger of coming up with something so unusual that you encounter an unknown phenomena and get caught unable to explain what is happening.

EDIT-1: When you say senior project, are we talking high school or college?

EDIT-2: I believe some undulations are for simply for rear view via the rear view mirror. Feel free to argue with or against this generalization.

Racin’ Today » Ingram: Hello Spoiler, Good-bye Rear Wing
http://www.racintoday.com/wp-content...ler-toytoa.jpg

Over or under - what ever works.

2008 Honda S2000 CR Prototype - Rear Spoiler - 1280x960 - Wallpaper
http://www.seriouswheels.com/pics-20...r-1280x960.jpg

This is certainly different - a fat and aggressive mid-plane.

Race Car Aerodynamics Package
http://www.hanleyinnovations.com/spoiler12.jpg

Another twist, must be a reason for not being a continuous section, right?

https://grassrootsmotorsports.com/fo...y/89454/page6/
https://lh5.googleusercontent.com/-c...219_155223.jpg

http://imgur.com/a/9pCMY There was a deliberate space in the link due to my then low post count. Anyway. As far as grades go, I'm not really sure. It's basically whether or not I make it to the conference (I got approved yesterday). I have plenty of wings to complete the project, I just wanted to see if anyone wanted me to test anything for them and also I have a bit of spare time and I'm always looking for cool ideas. It is a high school senior project. I'm 18 BTW.

I've already had a few weird things happen that I don't really know how to explain. It's not a big deal. I think it's pretty cool actually.

So as far as I understand, the reason why wings are twisted (basically different angle of attack on the sides vs the center or different airfoil) is because the air coming off the roof is flowing differently than the wing coming around the sides of the roof. This is because different wind characteristics make airfoils stall at different angles. Generally you want the most angle of attack without stalling the wing. You can learn more here https://www.youtube.com/watch?v=PmaKmz9cqRY (funny coincidence: the guy in this video is one of my mentors). With the NASCAR spoiler, I imagine that that is partially due to aerodynamics and partially due to visibility. Or if you recall that Ferrari FXX, really the place you need the downforce is on the sides (ie where the rear tires are) so the middle section is less important.

I have considered doing twisted wings and anhidrel/dihedral wings but that's only very recently. Basically every wing (aside from a few) have been sort of variations on that NASCAR spoiler you posted or flat drag style wings.

Do some research on vortex generators. The waves put a spin on the air (saw teath in center of the drag wing from pose #8).
I think the vortices form a kind of air curtain bridging the gap and contributing to faster reattachment when reaching the body.
---
Look inth aviation vortex generators they alow the air to turn faster than a general curves (template) insted of separation from the backglass being too steep ( in the green zonepost #4)
https://youtu.be/SXwVyxorvno
This guy duse a decent job of explain
https://youtu.be/9Whd_KnsLKE
At about 2:44 he gets into how to get more angle of attack wile maintaining attached flow.

Yes VG s add drag ,however, they prompt reattachment/ prevent sepperation .

I think you will see a massave change in the effectiveness of the spoiler/ wings you have already tested by wsing VG at the top of the rear window like an Evo Mitsubishi

Thanks for the suggestion gumby79, I have given some thought into shall we say, aero accessories (strictly to differentiate that sort of thing from a wing/spoiler). Other ones include, diffusers, front splitters, ground effects, etc. All would be very interesting to investigate. My worry is that they are beyond the scope of the project. The actual stated goal (or really the goal that got approved) is to find the optimal wing/spoiler/rear trunk attachment. Properly implementing any of these would require a significant amount of more testing. We shall see if I can fit it in, and if I can, I will.

Welcome to Ecomodder.

It's always entertaining to watch posters go right into the weeds. Let's step back.

An air tunnel at 1/24th scale? How many horsepower does this tunnel have? what's the cross-sectional area of the test section? Vortex generators at 1/24th scale?

Have you looked at graysgarage? He only posted for 4 months in 2015, so you sort of have to know to look for it; but that is a scenario that has some hope of returning viable results at 1/24th scale — upside down in water with hydrogen bubble jets.

Sawtooth trailing edges are used in High-bypass turbojets to moderate the acoustic signature.

I have no idea how much HP the wind tunnel has, It is the school's wind tunnel. I'm fairly certain it is a Pitsco Airtech 40. The top speed is 40 mph. The internal dimensions of the tunnel are 8" x 8". I actually made a mistake earlier in saying the car model itself is 1:24th scale, it is actually 1:25th.

As far as vortex generators go, I'm pretty certain I can print parts that small, but I am unsure if I will be able to detect any difference depending on how minute it is.

I have actually seen a number of their videos, very interesting stuff. I'm not super concerned about having data that can be transferred into real world values. The more important thing is comparing different setups.

Sounds like a fun project. But what are you optimising for? Downforce or low drag or a mix? I would experiment with a full boat tail and a half boat tail, with a vertical cutoff, oval shape. Low angle difuser underneath.
A boat tail is like a low drag baseline. I assume you've seen the aero civic?
Im sure you've heard of reynolds numbers right? Your paper wont mean much unless you test with similar reynolds numbers to real conditions. Good luck!

I'm not really sure yet. My best guess is that I'm shooting for the best downforce to drag efficiency. A boat tail sounds interesting I will look into it. I am somewhat familiar with the aero civic. And yeah, I have heard of the reynolds number. Since the project is mainly concerned with the difference between various setups, the number would be constant test to test. Please correct me if I am wrong.

I put a little time into this attempting to backtrack on my thoughts.

Background to the concept I presented is needed - and right now.

Biomimicry
Here's 7 of the Best Examples of Biomimicry and Nature-Inspired Design | Digital Trends

Aerodynamics by George Kachadoorian | Photobucket
http://i184.photobucket.com/albums/x...psev3omttc.jpg

And back in 2007............
New propulsion sytems for ships - Page 23 - Boat Design Forums
http://i184.photobucket.com/albums/x...psivdzs9ce.jpg

The fan/propeller from 2007 never came into being unfortunately.

The general idea here is to test a straight edge rear spoiler against a tubercle fin edge type.

The goals in mind would be the various angle of attack (vehicle in turns, going up and down hills etc.........) and measure the differences.

These straight edged spoilers we are so familiar with are perhaps just a reflection of man's linear thinking and surrender to manufacturing ease. Nature has some different things in mind apparently, and with 3D printing we can now give it a try.

2008
Bumpy whale fins set to spark a revolution in aerodynamics
http://newatlas.com/bumpy-whale-fins...dynamics/9020/
And the boat tread the article above was posted in including some discussion:

Whale of an idea for marine applications?
http://www.boatdesign.net/forums/boa...tml#post192994

1. You will need a baseline testing of the car model as stock, no attachments at all.

2. I suggest measuring a baseline for a standard aftermarket wing.

3. I suggest measuring a baseline for a standard rear spoiler similar to the one on your Z-car.

4. Once you have this baseline data you will have something to compare your new fangled designs to.

5. A definition of victory must be defined, a definition of "optimal" must be established. Is it to be low drag, high down-force, or some balance of the two set by some sort of complex math theorem or simple ratio?

If we are talking street cars versus racecars then look for minimum drag at zero lift. See materials written by Dr. Joseph Katz.

I asked about the power just so you'd think about it as a parameter. 40mph is viable.

8x8 is 64sq in. The closest model I have to hand is a diecast 1/24th VW Type III, close enough to a Civic. It is 2.75x2.25in or 6.1875sq in. That a blockage ratio of about 10%.

I will defer to another member, aerohead, on what the maximum blockage ratio should be.

He does good work, you could ask him.

Thanks for the info on Biomimicry. I'm not trying to complain or anything but the CAD software I use (Inventor) really does not enjoy making waves.

1. That was one of the very first things I did.

2. I sort of have that, there isn't really a "standard" rear spoiler but I could certainly test the more popular ones like for instance http://i126.photobucket.com/albums/p...1420060062.jpg this one is the same type of spoiler our racecar had before we slapped a huge superbird style wing to it (story for a different time).

3. I don't have a 240z, I wish. There was I think a spoiler that come with the civic model but it involved cutting into the trunk so that's out.

5. For the time being, the ultimate goal question is sort of one of those bridges I will cross when I get there. I think the downforce to drag ratio is an ok target.

I am very new to the world of wind tunnel testing and thus am relatively unsure of how the percent of blockage would effect results. Personally I think that as long as all the tests are down under mostly the same variables the numbers should be comparable.

http://ecomodder.com/forum/showthrea...low-34134.html

aerohead hasn't posted in a week, he's busy prepping for the A2 wind tunnel. The quote is from a similar thread.

I see elsewhere that blockage should not exceed 5%.

Check the local hobby stores or E-bay for 1/24th scale model kits.

A wind tunnel is like using a chain saw to slice onions, you get an idea about what might be happening, but the slices will look dramatically different.

The 3 primary differences between a wind tunnel and real life are,

1st) In real life, the car is moving through air that isn't. (Assuming a calm day) the drag created by the car is due to the energy required to move the air out of the way, and drag it along behind you. So, calm air just sittin there.....along comes a car, the air needs to move sideways/up/down to allow the car to pass. As the air is being shoved out of the way, some of it gets snagged on the car, or pushed along by it, making it move in the direction the car is going. In order for the air to move, you have to add energy to it, that is your drag. In the worst case, air moving at different speeds to get out of the way, and/or be entrained, creates differing air pressures due to the Bernoulli principle. When these differing pressures create a secondary air movement (Vortex) that secondary movement is also felt as drag, because, the air was just sitting motionless and the passing of your vehicle is what made it move, so the only place to get the energy to be moving comes from the car.

In a wind tunnel, the air is moving, and the car tries to slow it down.....can you see the significance? The wind tunnel car stops the air, the rolling car is starting the air.

2nd) The air affected by the car outside extends out many yards in each direction in front of, to the sides, and up. And by affected, I mean made to move....and we remember from before that making air move means energy expended. Behind the car, the air is in motion for many hundreds of yards before it settles back to being still and just sitting there again. Believe it or not, those air molecules hundreds of yards behind are still sort of attached to your car and anything that affects them, will be felt as a change in drag on your car.

In a wind tunnel, the sides and top of the tunnel don't allow the air to move like it would outside, and the air behind is seriously affected too. The rear wake has no opportunity to develop as it would outside, it is either ejected to still air, or turned around to be recycled way before it would have normalized. Either way, you lose how the air reacts outside, and thus have a different drag number.

3rd) The ground plane outside has still air sticking to it, as you drive over it, the air stuck to the bottom of the car is moving in the direction of the car. So outside, there is a shear effect happening, the air is essentially moving in 2 directions.

In a wind tunnel, the air on the ground and the bottom of the car are moving in the same direction....front to back. This is a dramatic difference, the air is moving very differently, thus, a different drag number.

There are other nuanced effects as well I'm sure, but these 3 are fairly glaring.

This is not to say that wind tunnels are complete crap, just that their results may not represent what a cars Cd will be in the wild. However, if you just want to see how one design element variation changes the aerodynamic characteristics of the car, it should work well. If nothing else, you learn a lot in how to conduct experiments, record data, and report the results.

I hope this helps you to understand things a little better. There is way more to aerodynamics than meets the eye. Also, what our intuition tells us is true, may need to be thought out much more deeply to understand the reality of it.

Aeroguy, I'm very heartened by your measured responses in this thread, and you seem to be a wicked smart person as well. With a keen intellect and good people skills, I'm sure you are going to be a massive success in what ever you choose to do in life. People like you make this forum very rewarding to participate in. Thanks for being here.

1/24-scale
 

Full-size automobiles achieve a stable coefficient of drag at around 20-mph.
Testing mods in full-scale would require at least a 20-mph test velocity.
--------------------------------------------------------------------------
At 1/24-scale,do to rules of dynamic similarity (verisimilitude),the air velocity in the test section of your wind tunnel would require a minimum 480-mph to achieve the necessary Reynolds number.This would introduce compressible flow/transonic flow effects which are not encountered in 'real' driving.
Typically,aero testing is conducted with a minimum 1/10-scale,and critical Reynolds number must be factored in.And this is 'rough' testing.
'Winners' from 1/10-scale tests would graduate to 3/8-scale,then winners from that would finally graduate to 1:1 scale testing,required to 'prove' a small structure as with a wing.
Exa Corporation's PowerFLOW CFD can analyze small features but require enormous digital CAD files,require 35-100 parallel computers running simultaneously to 'solve' a single iteration after many hours of run time.
--------------------------------------------------------------------------
You can learn some pick and shovel kinds of results at 1/24 so it can be worth playing around with it.

ChazInMT — I applaude your summarization. Even though my spell-checker rejects both those words. :)

aerohead — It's like the Cavalry coming over the hill.

aeroguy — Compare aerohead's description of legacy CFD against OpenVDB. It's currently being rolled into Blender. Blender's animation engine will enable open source Computational Fluid Dynamics.

Don't be too smug, you missed 1956 and the birth of rock and roll. :)

I agree with what everyone else has been saying about reducing Cd and lift if you can. I'm offering this example for reference because it is so iconic and well tested.

Sourced base image below because I could not find the one out of a book Aerohead scanned into his forum gallery which shows a template overlay.

https://en.wheelsage.org/porsche/911...ctures/o3rqv5/

Then I overlaid the one of the forum's AeroTemplates from here (not sure which page):
http://ecomodder.com/forum/showthrea...ion-21952.html

The combination:
Aerodynamics by George Kachadoorian | Photobucket
http://i184.photobucket.com/albums/x...psfts5pm3z.jpg

This overlay was done to provide some context for the chart quoted below, which shows a lowering of Cd and lowering of lift with ducktail.

Spoilers: front and or rear - Page 2 - Pelican Parts Technical BBS
Going back to one of my first comments about getting the rear spoiler to fill out the template, it looks as the Porsche 911 RS kept it just below that line for some reason unknown to myself.

Maybe your testing can examine what happens when you fill that gap in your comparative Honda Civic project. At what point does the Cd stop being lowered and starts going back up.

If your 3D printer does not allow for curved or wavy top edge of rear spoiler, then try a square notched or comb filter pattern, something like a bread knife edge.

The point would be to see if there is less drag when the vortex coming off the Gurney flap is broken down to smaller elements and is less planar or a constant cylinder of rolling air mass.

836 Gurney flaps - Aerodynamics - Civil Engineering Handbook
http://www.civilengineeringhandbook....02_250_427.jpg
Concept of wavy spoiler: Distribution of energy verses concentration of energy, which may help control oscillations.

If one "feathers" the edges as found in nature (bird feathers, whale fin tubercles) just to see what happens, there might be a nice surprise - or not.

Be brave, take a chance. Have no regrets because each failure is just another step in learning, and learning is a life long path - or at least it should be.;)

EDIT: One more chart.
http://forums.pelicanparts.com/porsc...ront-rear.html
http://forums.pelicanparts.com/uploa...1227215216.jpg

The 3.3 turbo tail is different than the spoiler type Ducktail, it extends out and is sometimes called a Teatray or Whaletail.

Similar to the below shown on a later model.
http://forums.pelicanparts.com/porsc...ront-rear.html
http://forums.pelicanparts.com/uploa...1227215362.jpg

I should note that there is less drag and less lift with the type shown on the red car (tray/wing) verses the earlier green car (duck).

If you go to Bonneville you are more likely to see rear mounted horizontal extensions than near vertical ones for the same reasons. Each one attempts to fill out the Aero-template in it's own way.

:confused:

Why is it that automakers of sleek/fast cars appear to make the top half of the car conform to the same curve as the template? (were the template only half the height of the car)

Especially if it isn't actually optimal?

I think your are talking about what I did a few years ago. However I was calling it "scaling the template down in size to fit the canopy".

It was explained to me this does not work because of the ground pressure wave consideration. In other words the template is sized for the height (high point), and that's that.

Now if you are looking at really low exotic cars, I have yet to see one lower than the template would allow for.

Either way, such a question is best poised with a graphic for clarification. Otherwise we can only guess at what you really mean.

The posts I'm thinking of are in the Aero-Template thread (a sticky thread), but also see Neil's post #58 in link below.

http://ecomodder.com/forum/showthrea...t-20793-6.html

Would a leaf blower producing 250 mph have enough volume for a wind tunnel?

Your "scaling it down to fit the canopy" bit was exactly what I was talking about, where you had the template superimposed over the canopy only. I saw a reply or two that said it wouldn't work but didn't really explain why.

Post #58 that you pointed out explains it a bit better. Didn't see that one. #72 was the reply I read. Maybe the terminology went over my head.

http://i346.photobucket.com/albums/p...psckmttqom.jpg

Is it just a coincidence that it scales almost perfectly? Or were they mistaken in the same way I am? Perhaps it's the shape the air takes as the front of the car pushes it up and over the whole vehicle that counts?

The glass/cockpit on a fighter jet also looks like a scaled-down version to me...
http://www.markstyling.com/home/FA-18F.jpg

I would think a specific angle would prevent separation, regardless of the scale of said object. And/or said angle might get smaller and smaller the faster said object is designed to go, so it would get "stretched" out more and more to prevent separation.

That's probably a lot more to this than seems obvious to someone uneducated about it, such as myself.

The basic purpose of the low aerodynamic drag game is to make air move the least amount possible.

Remember the air is still, not moving, you are moving through it. Anytime we make the air move it requires energy, the more we move it/energize it, the more energy it takes to do it. We can all agree on that?

I think the main point people miss is that as you push through the air, there is an ideal shape to make it as easy as possible for the air to get out of the way, and then return to a calm state as soon as possible. That is fairly easy to understand right?

What the (Thee) Template ©® represents? It is a shape that for a given size vehicle, it will move the least amount of air if the uppermost point on the template is scaled to be at the uppermost part of the vehicle, and the base of the template is at the bottom of the wheels.

The reason it does not scale, is because a vehicle of a given height is going to have to move the air up and out of the way in order to pass under it, as the air moves along the top back of the car, it will be energized the least and return to being still air again the soonest if the shape of the vehicle follows the curve of the rear of the template.

If the car shape is steeper in back, then the air will drop faster to return to calm, and by going faster will have more energy, thus more drag. If the shape is shallower, the air will have a longer opportunity to become entrained in the air being dragged along by the skin of the car, and be made to move more again, thus use more energy....which we see as drag.

If you just use the scaled Template ©® on design elements and called the vehicle optimized, then the top shape would be as aerodynamic as the bottom shape here.....

http://ecomodder.com/forum/member-ch...497-shapes.jpg

Annnnnd I don't think anyone is going to say that is true. Am I right?

But we can all agree that the top shape is better that the bottom here.....

http://ecomodder.com/forum/member-ch...98-shapes2.jpg

So yes, the template can help optimize elements....but, that's NOT what it is intended to be used for. You could use a 9 iron to putt with, or play tennis with a baseball, or use a crescent wrench to pound nails, but, you'd be doing it wrong.

Thank You...Please drive through.

Nice graphics Chaz, what program?

To answer Stubby's question, when I looked into this it included aircraft canopies and what I called equipment blisters.

Aerohead then posted information on these conditions for me/us. I dont know the specific thread but you can do a seach in the fourm to find it.

The shape was almost template matching, but stretched out in the front, not as blubous.

I recall doing a speed boat example if that helps.

EDIT: I looked up some old threads which explored the canopy and speed boat topics.

Canopy drag
http://ecomodder.com/forum/showthrea...rag-28206.html
http://i1271.photobucket.com/albums/...2/Scan2-14.jpg

And in another forum I posted a lot of related ground plane graphics, it's a boat forum so I was hoping for a different perspective there - I guess.

Teardrop Ratios - above deck
http://www.boatdesign.net/forums/hyd...eck-47575.html
http://origin-ars.els-cdn.com/conten...004327-gr4.jpg

This was a good example of "outside perspective" from that boat thread:
http://www.boatdesign.net/forums/hyd...k-47575-2.html
I think when we first look into these topics we assume what applies to aircraft also applies to cars, boats and maybe even hovercraft. However there are some differences regarding the affects of the ground plane or water plane.

Huge topic, I don't think one can do wrong getting started on any one of them, just don't mix and match expecting similar results/outcomes.

I've gotten comfortable using the "Draw" program in MS Word. It lets me do basic stuff, then I "Snipping Tool" what's on the screen to make it a .jpg. It's nice to be able to illustrate what I'm trying to convey to hopefully make it easier to figure out what I'm trying to say.

Yes.

Well... that and tradition. It's called a 'bubble-top coupe'. Examples (look 'em up yoseff) include the 64 1/2 Mustang, the Mercedes Benz 300SL coupe and my personal favorite — the 1961 Chevy Bel Air (and it corresponding Oldsmobile equivalent) 2-door hardtop.

As for the coincidence part, it falls apart in the front/rear view. For an example I'll point to the 1998 Plymouth Pronto Spyder

http://www.carstyling.ru/Static/SIMG...FBD1305BE34204
http://www.carstyling.ru/en/car/1998_plymouth_pronto_spyder/

What they found is it's hard to get side-by-side seating and a low windshield header. This is pushed about as far as it can go. Porsche Speedster-ish.

Now I will go back to waiting for OP to talk about wind tunnels.

Grant-53 — Big blower, little tunnel? It would need a diffuser section. That could be a bundle of soda straws. Or paper towel cores.